1. Field of the Invention
The present invention relates to a stenting catheter for transporting and deploying a stent in a branching anatomic duct having a stenosis attributed to a lesion commencing at the ostium, or entrance, of the branching duct and more particularly to such a catheter having a distal end portion including a forward facing abutment surface laterally offset from a proximal end of a forward extending stent carrier controllably positioned to align the abutment surface with the crux of the branching anatomic duct.
2. Description of the Prior Art
Angioplasty is a procedure involving the use of a balloon-tipped catheter to treat a narrowed anatomic duct such as a coronary artery. The catheter is used to advance the balloon mounted on the distal end of a catheter within the narrowed opening and then expand the balloon one or more times to compress arterial plaque and enlarge the narrowed opening. Anatomic ducts treated by angioplasty however can re-close within a short time (referred to as acute re-closure) or again assume a re-narrowing over extended time period (referred to as re-stenosis).
Stenting is a technique used to open blocked arteries in patients who have atherosclerosis. The blocked arteries can affect any organ system in the body but are most frequently approached with stenting when the lesion or blockage affects an artery supplying fluid to the heart, brain, kidney or legs.
The installation of a stent initially involves the same angioplasty procedure of placing a guide-wire across the blockage in the artery and then advancing a balloon dilatation catheter along the guide-wire to the site of the blockage whereupon the balloon is inflated to compress plaque and dilate the blockage. A selected stent arranged on a dilation balloon is advanced along the artery with the aid of the guide wire to position the stent along the site of the blockage. The balloon is inflated to permanently enlarge the stent against the wall of the artery leaving the stent anchored in place after deflating the balloon and removal of the catheter and guide wire. The stent serves as a prop in the artery to help prevent both acute re-closure and re-stenosis and also serves to maintain dilation of the vessel to prevent the treated area of the blood vessel from re-stenosis.
Treating a lesion with a stent in a branching anatomic duct represents a prevalent and a particularly difficult geometry to achieve placement of a stent at the exact location of atherosclerotic blockage. FIG. 1 illustrates an example of a branching anatomic duct 10 with atherosclerotic plaque 14 at the ostium 16 of a side branch duct 18 of a main duct 20. The side branch and the main branch form an angled relationship identified as angle .beta. which can be a right angle but usually an acute angle. FIG. 2 illustrates an example of improper longitudinal positioning of an end of the stent which as is well known cannot be corrected after deployment of the stent. A residual of treated atherosclerotic plaque 14A at the ostium 16 of a side branch duct 18 remains after the deployment of a stent 22. The protruding end 22A of the stent 22 extending from the ostium 16 into the main duct 20 becomes a partial obstruction that impedes the flow in both the branching duct 18 and the main duct 20. FIG. 3 illustrates a misplacement of stent 22 too deeply in the side branch 18 thereby leaving a residual of untreated atherosclerotic plaque 14B remaining as a blockage at the ostium 16 of the side branch thereby blocking flow into the branching duct. FIG. 4 illustrates a sub optimal placement of a stent in a branching duct where an arcuate segment 22B of the stent 22 overhangs the ostium 16 at crux 16A becomes a flow impeding partial obstruction. A residual of untreated plaque 14B remains immediately adjacent to ostium 16 also becomes a flow impeding partial obstruction.
It is an object of the present invention to provide a stent delivery catheter for placing a stent to a branching anatomic duct in a controllable position using the crux of the branching anatomic duct as a reference site.
It is another of the present invention to provide a catheter to rotatably position a stent carried thereby in a duct to orientate the stent at one lateral side of a duct for controllably positioning in a branching duct at a predetermined site.